You stated that the output from the diode looked the same (on the scope) loaded or unloaded but the output of that diode feeds pin 12 directly. How can the voltage be dropping on pin 12 but not on the diode.

Earlier, you stated that there was no difference between the loaded and unloaded waveforms on the tabs of Q3 and Q4. Now that you know that amplitude is important, do you see a difference loaded/unloaded?